Telegraph printing system



Feb. 24, 1942. J. A. SPENCER 2,274,103

TELEGRAPH PRINTING SYSTEM Filed Jan. 21, 1939 4 SheetS Sheet 1 m {Ff/ILM/TTEP 10 I INVENTOR.

LO/275% .rpz/vcm K. W

ATTORNEY.

TELEGRAPH PRINTING SYSTEM 4 Sheets-Sheet 2 Filed Jan. 21, 1939 A'l'fDEFGHI'JKL/fl/YOPOR'STUVfJXYZ IIIIIIII/IIII/II/I/I/I/III/IIIIII/I/IIII/II/I/ ATTORNEY.

J. A. SPENCER TELEGRAPH PRINTING SYSTEM Filed Jan. 21,1959 4 SI yeetS-Sheefo s IINVENTCR. JH/flff 14. JPf/VKf/F" ATTORNEY.

"Feb.24,.1942. 4 J. SPENCER 2,274,103

TELEGRAPH PRINTING SYSTEM.

ATTORNEY.

Patented Feb. 24, 1942 TELEGRAPH PRINTING SYSTEM James A. Spencer, Teaneck, N. J., assignor to Radio Corporation of America, a corporation of Delaware Application January 21, 1939, Serial No. 252,179

16 Claims.

This invention relates to printing mechanism for use in radio and wire telegraph systems.

In prior art tape transmitters and printers for simplex telegraphy using an equal length code,

' it has been necessary to utilize some of the units for local functions of the transmitter and receiver. In multiplex telegraphy it has been the practice to operate two or more transmitter tapes or printers together and perform the local function of one tape transmitter or printer while the next combination is being set up on another.

It'is an object of the invention to provide a system that utilizes all the circuit time for car ying equal length code signals and to operate the local mechanism of a device while another combination is being set up on the same device.

Another object is to provide a printing system for a single channel employing an equal length code, in which all the circuit time is used for the code transmission and reception. Another object is to provide an arrangemen for an equal length code by storing a part of a code, unit in a sending or receiving device for a sufficient time to permit such deviceto perform its local operations. I

Other objects will appear in the following description, reference being had to the drawings in which:

Fig. 1 is a conventional illustration of the trans mitting circuit and associated elements.

Fig. 2 is a view of the code characters for the 7 letters of the alphabet used in the system.

Fig. 3 is an illustration of the current pulses transmitted or received.

Fig. 4 is a conventional illustration of the receiving circuits and associated elements.

mitting ring H and a commutator l2 having seven contact segments over which sweeps shortmaintaining a given speed for the distributors at the transmitter and receiver are old and well known andare specifically not claimed herein,

such parts are not shown, reference, however, is made to patents to Callahan, Mathes and Kahn, No. 2,010,505, and Mathes Patent No. 2,028,375, which contain detail descriptions of such systems.

A second ring I4 and commutator l5 having seven segments are swept over by short-circuit brushes l6. These brushes rotate in unison with the brush [3 and in practice are preferably mechanically fastened thereto. I

The tape transmitter 10 contains seven seeker pins diagrammatically indicated at IT, adapted to pass through perforations in a perforated tape such as is illustrated in Fig. 2. This transmitter is operated by magnet I8 connected to contacts 5 and 6 of commutator l5. These seeker pins are old and well known in the art and are not illustrated but it will be understood that they areresiliently raised against the tape by appropriate mechanism. When a perforation occurs in a. tape in accordance with a message, the pins there beneath pass through the perforations andengage the superposed contact members. Since the time code used'consists of seven unit's there are seven of these contact members connected respectively to the coils ofrelays I to VII.

The coils of relays I, II, III'and IV are completed to ground directly through return wire IS. The circuit through the coils of relays V, VI and VII are completed through the switch contacts 20 when relay IX is energized and thence to ground through return wire l8. Relays V, VIand VII also have holding coils 2|, 22 and 23 energized by contacts closed by operation of the respective relays. The energizing circuit of these holding coils includes common conductor 24 and switch contacts 25 controlled by relay VIII. Re-

lay VIII has one terminal connected to the ground previously referredto herein, but not illustrated."

These brushes engage similarly numbered seg} ments at the same time. brushes l3 and [6 have just engaged contacts No. 5 by their rotation in the direction of the arrows 21, current from positive terminal 18' energizes coil 18' which clears the mechanical parts QI the transmitter 01 revious code com- Assuming that the binations by withdrawing the seeker pins below fifth and sixth seeker pins will pass through the perforations and engage their corresponding contacts. The remaining seeker pins being resiliently pressed against the tape will be prevented from moving against their respective contacts by the absence of perforations. At this time relay II becomes energized because its circuit is completed directly from positive terminal 28 through the seeker pin and contact to ground through conductor I9. The closing of contacts by seeker pins Nos. 5 and 6, however, do not energize the coils of relays V and VI because their circuits are ppen at contacts 20, relay IX being tie-energized. Positive potential is applied to segment 2 on commutator I2 by closure of front contact 29 of relay 2 but it is not transmitted to line because at. this time brush I3 is inengagement with contact No. 5. Relays V and VI will not place positive potential on segments 5 and 6 at this time because they have not been energized due to the open contactson relay IX.

The brushes l3 and I6 continue sweeping over the segments and engage contact members No. 1. Lower contact No. l is connected to the coil of relay VIII which becomes energized by current passing from positive terminal I8 through con-' ductor to ground wire I 9. This opens contact and deenergizes the holding coils of relays V, VI and VII if those relays have been previously energized. In other words, this is a clearing action. Upper contact No. l,is engaged by brush l3 on commutator l2 and negative potential is placed on ring II and outgoing line 3|. This forms portion 34 of the graph in Fig. 3. When the brushes engage contact No. 2 on the commutator a positive pulse 35 is sent out into the line 3| as'relay No. II is closed. When the brushes engage contact No. 3 negative pulse 36 is placed on line 3| since back contact 31 is closed. At this time brush l6 being on lower segment 3 of commutator l5, relay IX is energized from positive terminal I 8'. This closes contacts 20 and energizes selected relays V and VI. These relays have their holding coils energized at once as relay VIII is now de-energized.

When brush l3 engages segment No. 4 negative pulse 38 is placed on ring H and outgoing line 3| because relay IV is de-energized.

When the brushes engage segment No. 5 the upper brush l3 places positive pulse 39 on line gize relays l, 3 and 4. Positive potential will be applied to segments 1, 3 and 4 to commutator |2 but pulseswill not be conveyed to line 3| at this time because the brushes are on segment No. 5. It should be noted that even though the seeke pins have closed the transmitter contacts for the letter A, transmission of the previous letter H is still uncompleted.

When the brushes engage contact. segments No. 6 positive pulse 4| will be applied to line 3| because relay VI was previously energized for the letter H and the segment No. 6 in commutator I2 is connected to the positive terminal through make contact 42.

When the brushes engage segments No. 7 negative pulse 43 will be placed on the line 3| because back contacts 44 are closed. This completes the letter H and as just explained, the tape transmitter has been previously set for transmitting the letter A.

When the brush l3 engages segments No. 1, positive pulse 44, will be placed on outgoing line 3| because relay I is energized. Also, relay VIII is energized by action of brush l6 and contacts 25 are opened. This opens the back contacts 45 of relay V which were closed when this relay became energized through energization of relay IX on previous contact of the brush with segments No. 3. At that time this closed a holding circuit for relay V independent of contacts 20 on relay IX. The back contacts 46, 41, of relays is placed on line 3| by brush l3 and relay IX is energized by engagement of brush IS with segment No. 3. This immediately closes the circuit ofrelays V, VI and VII but since the seeker pins do not engage the contacts for these relays for the letter A nothing further happens.

, When the brushes engage segment No. 4 brush |3 places a positive pulse on line 3| because relay 4 is energized. When the brushes engage contact No. 5 negative pulse 60 is placed on line 3| and operating magnet l8 becomes energized which withdraws the seeker pins and steps forward the tape in the printer for the next letter which may be assumed to be N, but it should be again emphasized that even though the next letter N has been selected by the transmitter the cycle for the previous letter A has not been completed. This letter A is completed only when the brushes engage segments 6 and 7 and place negative pulses GI and 62, respectively, on line 3|.

It may be assumed that the next letter after formation of the letter N will be the letter D. The operation of the mechanism will now be clear and it will be unnecessary to trace out in detail the formation of letters N and D but the pulses have been shown in Fig. 3,

It will be seen from the foregoing that the tape transmitter is operated during the time that the fourth, fifth and sixth impulses are stored and hence all seven time units are available for the signal message itself.

The code partiallyshown in Fig. 2 allots three marking units and four spacing" units to each code character. This has been found to be decidedly advantageous in radio systems, particularly as the omission or addition of one or more units by static or other cause can never form,

a letter or other signal character which is the case with the five unit Baudot-code.

In Fig. 4 I have illustrated the circuit diagram of the receiver. On account of the similarity to the transmitter the operation will be understood =w'ithout detail explanationof the-various parts sized Relays RV and RVIienergize in succes- -but it should be. understood that the ringaand I sion printer selector magnets R5 and R8 which commutator segmentsar running synchronously and in phase. with those of the transmitter vby mechanism old in the art, and not illustrated.

At the transmitter in Fig. l'positive pulses are sent out for marking and negative pulses for spacing, as already referred to. 'The receiving ,operate their armatures by'projecting their ends into notches (indicated onlysfor relay RI) in selector bars 19 and 88 fragnientarily sh own in-Fig.

, 6. These selector bars are broken away but they 'circuit, however, is shown as arranged for current pulses. for marking and no current for spacing Therefore,-"somewhere in the link betweenthe transmitter and receiver the positive and negative pulses will be converted into on and ofi indications. In radio circuits this is done at the radio transmitting station before radiation takes place. At the radio receiving station the-received pulses are sometimes converted .matically illustrated as'siinple switch contacts 8L inFig. 6 which closes a circuit to relay but asshown in Fig. 4, the circuit is open at back into negative and positive pulses for line transmission to another point. In wire transmis-, sion, the positive and negative pulses may be re-.

ceived directly from the wire 3I at the trans- The positive and negative pulses reaching the receiving printer oflice, in any way, operates the polar relay 63 by energizing the coil 84 connected to the incoming line 65.

The operation of the receiving apparatus is'as follows: I a Referring -to Fig. 4 and assuming that the first negative pulse 34 of the transmitter letter H or other pulse formed therefrom, has arrived at the polarized relay 54, the switch tongue of therelay will be moved against dead contact 86 and no 7 current will flow when brush I3 engages segment.

No; l of commutator I8.

- 'fiow from commutator I5 at this time. I

' tact 81. At this time ':-'II. of relay RIX and it also energizes selector When positive pulse 35 arrives at relay 64 the relay tongue will be moved against positive-conon segments No. 2 an relay RII will be energized. The energization oftthis' relay closes its own holding. circuit to ground through contact magnet R2 of the printer (see also Fig. 6). In

the printer shown in Fig. 6 the latch and selector ton bar I5, there being a selector bar' for each selector relay. The armature is held in this position by latch I6 so that when the brush I3 leaves ushes I3 and Is will be have a series of properly positioned notches such. ;asnotch8I When relays R2, R5 and R8 operate their armatures each of them also closes contacts through a cut-out shaft and'lever diagramrelay RVIIL. Relay*RVIII has its coil connected to segment No. 7 on coimnutaton I5. .Therefore, when brush I6 engages segment No. 7 relay RVIlI is energized. Relay RVIlI opens the 'those relays for the next signal. Relay RVHI also energizedrelay R8 which closed switch contacts 82'and energized carriage magnet 83. Armature 84 then moves the printer carriage 81 (the middle portion being shown broken a ay) towards the left'by means of plunger 88.

Selector magnets RI to R1 and their respec tive armatures are mounted on carriage 81 and Also, no current wil as the carriage is moved to the left the selector bars 15,119 and 80, are moved therewith because the projecting ends of armatures l3of selector magnets R2, R5 and R8 .engage the edges of [notches identical with 145 Shortly before the motion to the left is completed trip 92 engages latch I6 and permits armatures "I3 to spring back into place. The armature is freed from irictionagainst the ends of notch I4 at this time by leaf spring 93 entering notch 94 in the three fselector bars whichfsnaps the selector bars slightly to the left. Similar trips (not shown) *release the other armatures; Selector magnets R, R5 and R8 then resume their normal condition. When the three selector bars reach their 1 extreme left-hand position notches 8| in the three selector bars correspondingrto the letter H are inalignment. Pull bar 88 shown more in When the carriage reaches its extreme move- "ment; to the left it opens switch contacts 98 segment No. 2 of the commutator the armature will remain in its operated position. The selector magnets RI to RT and their armatures and latches are all secured to the movable carriage 11,

When negative pulses 36 and 38 arrive in succession the switch tongue of polarized relay 84 will be thrown against the dead contact 66 and when brushes I3 and I6 engage contacts No. 3 and No. 4 in succession relays R111 and RIV will not be energized.-

-When positive pulse 39 arrives 'relay 64 will engage contact 61 andcurrent will energize relay RV as brush I3 is in engagement with segment No. 5. Relay RIX is also energized by brush I8 engaging segment No. 5. This opens the holding circuit for relays I and IV to clear them for succeeding signals. When brush I3 engages segment No. 6 pulse 4I causes relay RVI to be enerand breaks the continuity of the holding circuit ofrelay R8 This deenergizes {the relay and opens the contacts 82 which in turn deenergizes carriage magnet 3. The carriage return spring 9| thereupon ret ms the carriage to the right As the return lever 95 snapped into the notch of latch 91 printing contacts 98 closed and printing relay 99 was energized. This. closed contacts I and energized printing solenoid IOI.'

This solenoid pulls the armature I02. downward with its extension I03 which is pivoted to printing bail 89, the bail being pivoted at an intermediate point I04. This moves the bail upward (Fig. 'I) and permits the pull bar 88 to drop into th aligned notches BI (Fig. 6) in the holding circuit of relays R5 and R6 clearing" selector bar s. As it does this the upwardly moving projection I05 engages the shoulder I06 in the pull bar and moves it upwards with the bail. This throws type bar I01 downwards and strikes the type-pallet against the ribbon on platen I08. This prints the letter H.

Just at the time that the armature I02 of the printing solenoid completed its movement projection I 09 engaged the latch 91 and permitted the return lever 95 to return the three selector bars to the right whereupon leaf spring 83 snapped into groove I II) which holds these three bars together with the others in their initial position. At about this time projection I II opens switch contacts H2 and 'deenergizes the printing relay and the printing solenoid plunger is returned to its initial position by spring II 3. This returns the pull bar and brings the printing bail 89 against the hump of the pull bar and moves it outwards clear of the selector bars.

The selected letter H has thus been printed and all mechanism of the printer has returned to the original position. However, the selection of the next transmitted .letter was not held up pending the operating of theprinting mecha nism. Since the holding coils of relays RI and RIV were opened by relay RIX when the brush I6 was on the fifth segment those relays were thereafter available for subsequent signals. The selector magnets assumed their inoperated position before the printer magnet was energized so signals in RI to RIV can be stored in the printer as soon as the brush I3 reachestheir corresponding commutator segments. Since the holding circuit of relays RV to RVH was opened when the brush energized the seventh segment, those relays were then made available for further signals. In view of this the printing mechanism has substantially one full revolution of the commutator for completion of the printing operation itself. During this printing operation the signal code reception continues without interruption as the impulses, in effect, are

' stored in the relays while the printing is completed. I

The letters A, N and D will be printed in a manner similar to the letter H by operation of the required combination of selector bars.

Since the printing system of my invention operates independently of the tape transmitters connected thereto to be closed when the operating coil is energized, a second commutator having spaced segments, a brush adapted to run in synchronism with the first mentioned brush for connecting the last mentioned segments successively to a potential source, an additional relay having its operating coil connected to a segment of the second mentioned commutator unit equal length code characters, a communication channel, a tape transmitter having contact closers, a series of relays each having an operating coil, a switch tongue and two switch 7 contacts, said coil being connected to one of said contact closers,. said ,switch contacts being connected to opposite terminals of a potential source, and said switch tongue being in engagement with one of said switch contacts when the said coil is energized and with theother when it is de-energized, a commutator having spaced segments each connected to one of said switch tongues, a brush adapted to move over said segments and connect them successfully to and printers of other channels, its greatest advantage over prior art systems is in single channel printing operations.

I have illustrated circuit arrangements that have been found satisfactory but the invention is not to be limited thereto as various changes could be made without departing from the spirit .of the invention.

Having' described my invention, what I claim is:

1. In an electric telegraph system for multiunit equal length code characters, a communication channel, a tape transmitter, relays each having an operating coil and a switch, each coil being connected to said tape transmitter,- a'

the outgoing line of said communication channel, a number of relays being storing relays each having a holding coil containing a switchadapted to be closed when the operating coil is energized, a second commutator having segments spaced similarly to the first, third and fifth segments of the first mentioned commutator, a brush adapted to run in synchronism with the first mentioned brush for connecting the last' mentioned segments successively to a potential source, an additional relay having its operating coil connected to a segment of the second mentioned commutator and adapted when energized to open the circuit of said holding coil, a further relay having its operating coil connected to another segment of the second mentioned commutator and adapted, when energized. to close the circuit of the operating coils of the storing relays, and. an operating coil for the tape transmitter, the last mentioned coil being connected to the remaining segment of the second mentioned commutator, said coil moving the tape to set up new code'combinations when the last I mentioned segment is contacted by its brush.

3. In an electric'telegraph system for sevenunit equal length code characters, a communication channel, a tape transmitter having seven contact closers, seven relays each having an operating coil, a switch tongue and two switch contacts, said coil being connected to one of said contact closers, said switch contacts being connected to opposite 'terminals of a potential source and said switch tongue being in engagement with one of said switch contacts when the said coil is energized and with the other when it is de-energized, a commutator having seven segments each connected to one of said switch tongues, a brush adapted to move over said segments and connect them successively to the outgoing line of said communication channel, three of said relays each having a holding coil and a switch therefore adapted to be closed when I operating magnet for moving the selector bars,

to each of the segments of said commutator, a 1 selector magnet having means for coupling said the operating coil is energized, a second commutator having three. segments, circumferentiaily positioned similarly to the first, third and fifth segments of the first commutator, a brush running in synchronism with the first mentioned 5 relays, and an operating coil connected to the fifth segment of the second mentioned commutator for moving the tape of the tape transmitter to a new position whereby new circuit combinations are set up by the tape transmitter 2 when the fifth segment has been contacted by the brushes without destroying-the fifth, sixth and seven circuit combinations previously set up thereby. I

4. In'an electric printing telegraph system for, 2 a multi-unit equal length code, an incoming line carrying successivepulses representing the units of each'code character, a commutator having as many segments as the number of units .in

segments assigned the initial units of the code characters having holding coils, a second 1mm: mutator'having two spaced segments,-means for I cyclicly connecting the segments of the last mentioned commutator to a potential source, means connected the leading segments of the last mentioned commutator for opening. thecircuit of said holding coils, and means for connecting the trailing segment of the last mentioned commur tator to said operating magnet. I

7. In an electric printingtelegraph system for a multi-unit equal length code, an incoming lin for carrying successive pulses representing th units of each code' character, a commutator having as many segments as the number of units in said code characters, means for eyclicly con necting the incoming line successively-to said segments, aprinterha-ving selector bars, a selector magnet'for each selector bar and an oper-" ating magnet for moving the selector bars, a relay having an operating coil-connected to each, of the segments of said commutator for energizmutator having tWO SDaGGd segments, means for cyclicly connecting the segments of the last mentioned commutator to a potential source,

means connected to one of the segments of the said codecharacters, means for cyclicly connect- 30 last mentioned commutator for Opening the ciring the incoming line successively to said segments, a printer having selector bars, an operating magnet for moving the selector bars, a

selector relay having an operating coil connected to each of the segments of said commutator, a

selector magnet having means for coupling said operatingmagnet to the selector bars and means for continuing the energization of a plurality of the selector relays after the incoming line is disconnected from their operating coils, and

- necting the incoming line successively to said 0 segments, a printer having selector bars, an operating magnet formoving the selector bars, a selector relay having an operating coil connected operating magnet to the selector bars and means for continuing the energization of a plurality of the selector relays after the incoming line is disconnected from their operating coils and means for energizing the operating magnet after a plurality of the selector relays are de-energized.

necting the incoming line successively to said segments, a printer having selector bars, and an a relay having an operating coil connected to each of the segments of said commutator having means for coupling said operating magnet to the selector bars, the relays connected to the 7 cuit of said holding coils, and means for connecting the other segments of the last mentioned commutator to said operating magnet.

8. In an electric printing telegraph system for a multi-unit equal length code character, an in- 7 coming line for carrying successive pulses representing the units of each code character, a commutator having as many segments as the number of units insaid code characters, means for cyclicly connecting the incoming line, successively to said segments, aprinter having selector bars, a selector magnet for each selector bar and an operating magnet for moving the selector bars, a relay having an operating coil connected to each of the segments of said commutator for energizing said magnets, the relays connected to the segments assigned to the initial units of the code character having holding coils, a second commutator having two spaced segments, means -for cyclicly connecting the segments of the last mentioned commutator to a potential source, means connected to one of the segments of the last mentioned commutator for opening the circuit of said holding coils, and means for connecting the other segment of the last mentioned commutator to said operating magnet.

9. In'an electric printing telegraph system for seven-unit length code characters, an incoming line for carrying'successive pulses representing the units of each code character, a commutator having seven segments, means for cyclicly connecting the incoming line successively to said segments, a printer having sevenselector bars, seven selector magnets andan operating magnet for moving the selector bars, four relays having operating coils connected to the firstfour of the segments of said commutator for energizing four of saidselector magnets, said relays having holding coils, means to connect the remaining segments of said commutator to the remainder, of said selector magnets, a second commutator having two segments circuinferentially spaced similarly to the fifth and seventh segments of the first mentioned commutator, means for cyclicly connecting the segments of the last mentioned commutator to a potential source, means connected to one of the segments of the last mentioned commutator for opening the circuit of said holding coils, and means for connecting-the other segment of the last mentioned commutator to said operating magnet.

10. In an electric printing telegraph system for seven-unit equal length code characters, an incoming line for carrying successlvepulses representing the units of each code character, a commutator having seven segments, a. brush adapted to connect the incoming line successively to said segments, a printer having seven selector bars, seven selector magnets and an opcrating magnet for moving the selector bars,

seven relays having operating coils connected to l segments of the last mentioned commutator to a potential source, another relay having an operating coil connected to one of the segments of the last mentioned commutator adapted, when energized, to open the circuit of the holding coils of the first four of the first mentioned relays,

a further relay having means to open the circuit of the holding coils of the remainder of the first mentioned relays and to closethe circuit of said operating magnet and means to connect said further relay to the other segment of the last mentioned commutator.

11. In an electric telegraph system for multi- I unit equal length code characters, a communication channel, a plurality of relays having coils and switch tongues, part of said relays having means for holding them in operated position, a distributor for continuously connecting said switch tongues successively to said channel in successive cycles, a code transmitter having switches in circuit with said coils, an additional switch in circuit with coils of the last mentioned relays, means for operating said code transmitter to close the first mentioned switches of the coils for a new code combination before the transmission cycle of the previous code combination is completed, means for closing the additional switch in the next succeeding cycle before the switch tongues of the last mentioned relays are connected to the said channel in that cycle, and means for causing the first mentioned means to restore the relays to inoperated position before said additional switch is closed.

12. In an electric telegraph system for multi unit equal length code characters, a communication channel, a plurality of relays having coils, switch tongues and pairs of contacts, part of said relays being storing relays with means for holding them in operated pos'ition, the switch tongues being normally in engagement with one of the contacts, a distributor for continuously connecting said switch tongues successively to said. channel in successive cycles, a code transmitter having switches in circuit with said coils, an additional relay having a switch in circuit with coils of said fore the switch tongues of the last mentioned relays are connected to the said channel in that cycle, the closing of said additional switch energizing coils for moving the switch tongues into engagement with the other contacts of said pairs, and a further relay energized before said additional relay'for causing the first mentioned means to restore the relays to inoperated position.

13. In an electric telegraph system for multi unit equal length code characters, a communication channel, a plurality of relays haying operating coils, switch tongues and positive and negative contacts, the switch tongues being normally in engagement with one of said contacts, a distributor for continuously connecting said switch tongues successively to said channel in successive cycles, a code transmitter having switches in circuit with the operating coils, an additional switch in circuit with the operating coils of a part only of said relays, the last mentioned relays having holding coils, a clearing switch in circuit with each of the holding coils, means for operating said code transmitter to close the first mentioned switches for a new code combination before the transmission cycle of the previous code combination is completed, means for closing the additional switch in the next succeeding cycle before the switch tongues of the last mentioned relays are connected to the said channel in that cycle, the closing of the additional switch energizing the operating coils for moving the switch tongues into engagement with the other contact, and means for opening the clearing switch in said next succeeding cycle before the closing of the additional switch.

14. In an electric telegraph system for multi unit equal length code characters, a communication channel, a-plurality of relays having operating coils and switch tongues, part of said relays being storing relays, a distributor for continuously'connecting said switch tongues successively to said channel in successive cycles, a code transmitter having switches in circuit with said coils, an additional relay having a switch in circuit with the operating coils of said storing relays, the storing relays having holding coils, a clearing relay having a switch in circuit with said holding coils, means for operating said code transmitter to close the first mentioned switches for a new code combination before the transmission cycle of the previous code combination is completed, means for energizing the clearing relay in said next succeeding cycle and means for energizing said additional relay in that cycle after the energization of the clearing relay.

15. In an electric telegraph system for multi unit equal length code characters, a communication channel, a plurality of relays having coils and switch tongues, a distributor for continuously connecting said switch tongues successively to said channel in successive cycles, a code transmitter having switches in circuit with said coils, an additional switch in circuit with coils of a part only of said relays, means for operating said code transmitter to close the first mentioned switches for a new code combination before the transmission cycle of the previous code combination is completed, means for closing the additional switch in the next succeeding cycle before the switch tongues of the last mentioned relays are connected to the said channel in that cycle, and means for restoring the last mentioned relays to normal in said next succeeding cycle before the additional switch is closed in that cycle.

16. In an electric telegraph system for multi unit equal length code characters, a communicae tion channel, a plurality of relays-having coils,

, switch tongues and pairs of contacts, the switch tongues being normally in engagement with one of the contacts, a distributor for continuously connecting said switch tongues successively to said channel in successive cycles, a code transmitter having switches in circuit with said coils, an additional switch in circuit with the coils of a part only of said relays, means for operating said code transmitter to close the first mentioned switches of the coils for a new code combination before the transmission cycle of the previous code 

